Automotive tire inflation system

Abstract

A computer based system for adjusting the pressure in pneumatic tires prompts the operator for pressure and vehicle type information. Comparison of vehicle type with predetermined pressure ranges is used to detect erroneously entered pressure values. A display device visually indicates the operation sequence along with displaying pressure and system error and operator error messages. A remote pressure sensor is used together with a intermittent inflation/deflation schedule to permit equalization of the hose and tire pressure without metering valves. Monitoring historical hose pressure is used to detect a number of failure modes.

I claim: 
     
       1. A controller for adjusting the pressure of pneumatic tires for vehicles from a source of pressurized air comprising: an air flow valve connected at one end of an elongate hose extending to the pneumatic tire, the valve permitting the flow of air between the valve and the pneumatic tire through the hose, when in an open state and preventing the flow of air between the valve and the pneumatic tire through the hose when in a closed state;   a data entry terminal permitting the entry of a desired inflation pressure for the pneumatic tire;   a pressure transducer attached to the hose between the valve and the tire, the transducer providing a reading of a hose pressure of air within the hose; and   an electronic computer receiving data from the data entry terminal and the pressure transducer, connected to the air flow valve, and operating according to a stored program to: a) close the air valve for a first predetermined time interval sufficient so as to equalize the pressure between the the hose;   b) read the hose pressure after step (a); and   c) if the desired inflation pressure differs from the hose pressure open the air flow valve for a second predetermined time interval and repeat steps (a) through (c)     wherein the electronic computer also operates according to the stored program to:   (i) read the hose pressure inflation pressure at an initial repetition of step (b) to determine a first reference hose pressure;   (ii) count the number of repetitions of step (b) until a later repetition of step (b);   (iii) determine at the later repetition of step (b) a second reference hose pressure;   (iv) calculate a difference between the first and second reference hose pressures; and   (v) cease repeating steps (a) through (c) if the number of repetitions exceeds a predetermined count and the magnitude of the difference is less than a predetermined limit.   
     
     
       2. The controller of claim 1 wherein step (v) also causes the electronic computer to display an error message indicating one of the group consisting of: stuck inflation valve, stuck deflation valve, loose chuck, failed pressure transducer. 
     
     
       3. The controller of claim 1 wherein the open state permits the flow of air from the source through the valve of the pneumatic tire to inflate the pneumatic tire. 
     
     
       4. The controller of claim 1 wherein the open state permits the flow of air from the pneumatic tire through the valve to the atmosphere to deflate the pneumatic tire. 
     
     
       5. A controller for pressurizing pneumatic tires for vehicles from a source of pressurized air comprising: an air flow valve connected at one end of an elongate hose extending to the pneumatic tire, the valve permitting the flow of air between the valve and the pneumatic tire through the hose, when in an open state and preventing the flow of air between the valve and the pneumatic tire through the hose when in a closed state;   a data entry terminal permitting the entry of a desired inflation pressure for the pneumatic tire;   a pressure transducer attached to the hose between the valve and the tire, the transducer providing a reading of a hose pressure of air within the hose; and   an electronic computer receiving data from the data entry terminal and the pressure transducer, connected to the air flow valve, and operating according to a store program to:   (a) read the hose pressure inflation pressure at an initial time to determine a first reference hose pressure;   (b) open the air flow valve for a first predetermined time interval;   (c) read the hose pressure inflation pressure at a subsequent time a predetermined time after the initial time to determine a second reference hose pressure;   (d) calculate a difference between the first and second reference hose pressures; and   (e) display an error message if the magnitude of the difference is less than a predetermined limit.